Carburetor



' Feb zs, 1930.

W. T. SIMPSON CARBURETOR Filed Sept. 8, 1924 Fuel 6'0 /y Znuen for:

atented Feb. 25, 1930 E TAT PATENT, orrie-a WARD T. SIMPSON, OF GBAND RAPIDS, MICHIGAN, ASSIGNOB TO ALBERT G. D1081] SON, OF GRAND RAPIDS, MICHIGAN cmuaaron Application fled September a, 1924. semi Io. 13am.

The invention concerns a system of supplying 'fuel to an internal combustion engine in which the usual vacuum tank is dispensed with and instead. vacuum depression is created in the fuel bowl to draw -fuel from a low level supply tank, and the invention "consists in the features hereinafter described, and particularly pointed out in the claims: In the drawings:

Figure 1 is a vertical sectional view In the nature of a diagram,-some of the parts being displaced from their position in practice to make the view more comprehensive. Fig. 2'is a side view of an automobile with my improvement attached. 1

which .fuel is led from a low level tank, through a strainer 2, a pipe 3, and a valve 4 which is controlled by a link 5 from a float 6 pivoted at'7. The fuel'passes out from the bowl past a needle valve 8 and through a passage 9 to atube 10 forming -a part of the'mixture' nozzle which also includes an air tube 11 surrounding the fuel tube. The needle valve is pressed by a spring 12 tending to force the valve to closed position, the

I open position of the valve being determined by any suitable means of adjustment.

The nozzle discharges into a mixing chamber 13 which is the'cylindrical space above the nozzle and below the throttle valve. The

mixing chamber at its upper end is directed to "the engine intake and is coax 'ially ar-" ranged therewith. There isfa vacuum passage 16 communicating the space in the fuel bowl above the fuel level with the engine intake, and the mixingchamber is in-communicationwith this passage. The air tube 11 of the mixing nozzle directs primary air 45 edge and-the adjacent wall of asleeve valve through the restricted space 17 to the mixing the formation of the tip of the nozzle is In these drawings 1 is the fuel bowl into' ed in thevair inlet 22, the connection being to the restricted passage between the upper 18 slidably mounted within and against the inner side of the mixing chamber. ThlS valve controls the admission of secondary air to flow along the outer side of the nozzle chamber, and for this urpose the valve moves towards and from the enlarged base 19 of thev nozzle according to variations in the demand of the engine. The nozzle is provided-with a frusto-conical tip and the result of to create a conical vacuum space above the nozzle which causes a flow of fuel therefrom I by inducing a high velocity of primary air through the air nozzle. A throttle valve 20 is pivotally mounted 1n the engine intake and any suitable con nection is employed leading to within reach of the driver .for operating it. This valve is connected with a valve 21 pivotally mount made by a link 23 so that both valves are operated in unison to open or close simultaneously.

At 24 is arranged a-.valve for the admis- 7 sion of hot airto the interior of the air tube of the mixture nozzle and to the mixing chamber when the sleeve valve 18 opens. This hot airvalve opens inwardly against the pressure of the spring which tends from the. interior of the casing to supply air to sald valve to compensate for any leakage that may-take place at said valve. when 1 port- 34 and the piston head 30 has a port 35.

The piston is pressed downwardly by a spring 36 hearing against the upper piston head 37 and the top wall of the chamber 38 in which the upper piston works. This chamber is in communicationby a passage 39, with the air intake of the engine at a point above theithrottle valve. A fuel discharge pipe.40 leads from thelower part of the accelerator fuel well3l through the passage 16 :to discharge fuel just below the throttle valve 20.- Theou'tlet from this pipe isofl' to one side of the mixing chamber so that there will be no aspirating effect of the flow of mixture from the main noz zle there- Operation In 'startingthe valve 26 is operated manually to open position, thus placing the engine intake at .a point above the/closed throttle valvein. communication with the fuel a bowlthrough the pipe 28. On crankingthe engine, vacuum depression is created within the carburetor, which varies at different points, the greatest degree of depression being at .the'iengine intake above the closed throttle'valve 20. IThis will induce fuel to flow from the bowl through the pipe 28 and open starting valve 26 into the engine intake above the throttle valve. Air will pass through the passage 29 to mingle with the fuel on its way through the starting valve, to aid'in atomizing the fuel as it merges into the. engine intake. 4 n Having started the motor, the starting valve 26 is closed by operating the manual connection. .Fuel will now flow' from the fuel chamber-past the tapered needle valve 8, through passage 9 and tube 10 into'the mixmg chamber, this-actionbeing induced by the suction of the engine, it being understood that the throttle valve,even when closed, willleave suflicient opening to .permit this suction to be exerted'on; the mixing I chamber and noz zle, thus inducing an upward flowof air through theannular space at the upper end of the same, due to slight against the pressure of its suction, an

' r passing the valve,- the air pr g- ,reaches thespace-42 through port 41.. This air, as above described, comes from a jacket or the like, arranged to be'heated from the exhaust manifold so that soon after the en- I cally set ready to deliver a charge of fuel to the engine intake as soon as the throttle r valve is opened. The setting of the accelerating mechanism ready to act takes place by reason of the suction onthe piston 37 exerted through the passage 39 from the port 43 located in the engine intake above the closed throttle valve. This 'suctionl, raises the piston against the pressure of its spring and fuel will now pass through port32 into the well 31 and below the lower head 30 of the accelerating piston. It will be ob&

served that with the throttle valve closed there will be no substantial vacuum in the fuel chamber such as oppose the upward the spring 36. ,Now, by quickl opening the th rottle valve, there will take p ace an equal-' 'ization of the vacuum depression between the engine intake and thefuel chamber or bowl and the spring 36 will now exert its force and move the piston down so that its lower head will press the fuel. below it through .the tube-40 'to the engine intake to enrich the mixture for rapid acceleration. If the throttle valve is opened slowly, instead of quickly as above described, the pulsation ofthe engine will be communicated through the passage39, causing the piston to reclprocate and alternately pump fuel and suck it back.

, There is a critical point in the range of openmg of the valve 20 at which the accelerating piston 30, 37 will tend to res 0nd to the pulsations of the engine and pro uce this undesirable pumping action up and down of the piston. This critical point is when the 'throttle valve 20 has partly opened and thus partly broken the vacuum in the cylinder 38, thereby allowing the piston 30 to descend part way. When this position is reached the piston becomessensitive to the pulsations of the engine and the undesirable reciprocating gaction would ensue if means were not provided to prevent it.- To prevent this-pumping action, the small openings 34i\and 35 in the .hollow'. piston rod and in the .lowerhea'd of the accelerator e of the -piston, .the fuel will rise through the port .'or opening 35 in the .head of the piston and the-fuel rising in the I hollow stem of the piston forces aii out within the air nozzle and the restriction 17 j r g are'provlded'v on the through the opening. tee-which thus acts as a breatherhole.

If the throttle valveis closed for instance in turning a'corner, the suction will be cut off from the fuel chamber, but will exist in the passage 39 thus overbalancing the suction force in favor of lifting the piston against the tension of the spring, which lifting action now takes place, thus setting the accelerator for the quick pick up of the engine when the driver againopens the throttle valve after rounding the corner.

When the throttle valve 20 is opened, the connecting link 23 causes the valve 21 to open also. The degree of depression in the space 42 is decreased immediately to approximately atmospheric pressure and" as a result the spring 25 closes the ball checkvalve 24 to its seat thus shutting off the hot air at substantially the same time thatcold air is admitted throughthe valve 21, the hot air no. longer being desirable. When the valves 20 and 21 are opened the suction of the engine causes air to rush upward to the engine intake. This inrushing air passes up through the air nozzle 11 and past the tip of the fuel tube 10. The suction of the engine raises the sleeve valve 18 from its opposing member or seat 19, thus opening the air inlet at 19*,

and air now rushes up through the valve 18 and past the restricted passage 17 between the flared upper end of the nozzle and the sleeve valve 18, and the friction of the air against the inner side of the valve serves to lift it. The main function of the sleeve valve is to maintain substantially a uniform vacuum depression inth'e top of the fuel chamber for all speeds of the engine, to draw fuel from the low level storage tank into the fuel chamber 1. A

I claim: y

1. An apparatus of the kind described in which substantially equal pressures are maintained in the constant level fuel reservoir and mixing chamber by means of a direct communication between them, an e ector, a throttle valve, and means for automatically supconsisting of a piston for driving a charge of fuel from a well, said well being open at its upper part to the area of low pressure above the fuel level in the reservoir and communicating with the reservoir below the normal level of fuel therein and with an outlet in the mixing chamber wall at a point elevated above the normal fuel level, said piston having in its head a by-pass port and being joined by a rod to another piston on which a spring impinges, said. spring belng stressed by the suction of the engine when the throttle is closed, and released to force down the pistons when the throttle is quickly opened.

2. In an apparatus of the kind described an acceleration device consisting of, a chamber open to the fuel reservoir both .below and above the normal level of fuel therein, and

containing two pistons joined by a rod, the space below the upper piston being-that which opens into the fuel reservoir, the space above the upper piston communicating by a passage to the engine intake to be subjected to suction when the throttle is nearly closed, said pistons being pressed by'a spring abovethe upper one, the .suction retracting said spring when the throttle is below said communication, the spring being released by the opening of the throttle, and driving a charge of fuel from the lower part of the chamber out through a tube into the mixing chamber, the lower piston having a by-pass port through which fuel may pass, said bypass port and the elevation of theoutlet tube combining to prevent the emission of fuel from the tube when not intended, both fuel well and outlet tube being under the same pressure.

3. An apparatus of the kind described for supplying and carbureting fuel for internal combustion engines in which subatmospheric pressure is maintained for the primary purpose of lifting fuel from a main supply reservoir, this pressurebeing substantially the same in the fuelcchamber of-the apparatus and in the mixing chamber, which chambers arein open communication, and an ejector for forcing fuel into the mixing cba [1'1- ber and atomizing the fuel, and having as part of its assembly a substantially cylindrical sleeve valve which by its weight controls the aforesaid pressure, and by its movement admits air which joins with otherair in the operation of the ejector, the cylindrical form of said valve enabling it to rise without affecting the form of the passage it controls, and an accelerating device designed to operate independently of the ejector action and which is actuated by suction when the throttle is closed stressing a spring which drives a piston against a charge of fuel when said suction is released by movement of the throttle,-the said piston having a'by-pass port cooperating with an outlet pipe terminating hi h above the normal fuel level to nullify the e ect of pulsations in the suction, said acceleration means being adapted to the substantially equal pressure surrounding it, and an anterior air valve operating in unison with the throttle to govern the pressure below the ejector to permit this low pressure to actuate an alternative air inlet valve which is spring controlled and which leads to a source of hot air, said outer air inlet valves by their presence slightly intensifying, through the communication between mixing and fuel chambers, the subatmospheric pressure which lifts fuel, and permitting the use of a lighter sleeve valve than would otherwise be necessary.

4. In combination in a fuel supply system for internal combustion engines, a fuel chamber, an engine intake and mixing chamber in direct communication with the fuel chamber above the fuel level therein, a sleeve'valve having a cylindricalinterior, an ejector extending coaxially into said valve, having a fuel passage, said ejector having an outwardly flared enlargement at its end} forming between itself and the cylindrical inner side of the-sleeve valve anannular restriction for the passage of air, the area of said restriction being constant at all positions of-the valve,

said sleeve valve moving automatically along the mixing chamber under varlatlons 1n the f suction of the engine, and supplying more air below said restriction in accordance with its movement into the mixing chamber.

5. In combination in a fuel supply system for internal combustion engines, a fuel cham- -ber, an engine intake and mixing chamber a in direct communication with the fuel chamber above the fuel level therein, a sleeve valve having a cylindrical interior, an annulai seat for said valve between which and the lower edge of the valve the air enters from all sides uniformly when the valve is raised, an ejecsaid seat and having a fuel passage and a primary air passage, said ejector having an outwardly flared enlargement at its end forming between itself and the cylindrical inner side of the sleeve valvean annular restriction for the passage of secondary air, the area of said restaiction being constant at all positions of the valve, said sleeve valve moving automati- :fuel from the reservoir and delivering it atomized into the mixing chamber, consisting of an e ectorhavinga f-uel tube and an air tube surrounding the same, a throttle valve at the engine intake, and two air inlet valves at the intake of the apparatus, one, spring loaded, and operating automatically, the other, linked to the throttle and moving uniformly therewith, said ejector having an annular passage aboutvit for secondary air, a sleeve valve controlling said annular passage vacuum depressionin the mixing chamber, said two valves supplying air to said air tube and annular passage, substantially as described.

7. In apparatus of the kind described and in combination a mixing chamber and fuel chamber connected so that vacuum depression will exist over the fuel substantially equal to that in the mixing chamber, an ejector for delivering fuel from the fuel chamber to the mixing chamber, an accelerator consisting of a piston and cylinder for forcing fuel from the fuel chamber to the mixing chamber, a throttle valve, said cylinder being in communication with the fuel chamber, and in connection with the intake above the throttle valve, and a spring for'forcing said piston to deliver fuel to the mixing chamber, substantially as described.

In testimony whereof I a'fiix my, signature.

- a WARD T. SIMPSON.

vtor extending coaxially into said valve from' and operating automatically according to the 

